A low proportion of asymptomatic COVID-19 patients with the Delta variant infection by viral transmission through household contact at the time of confirmation in Ibaraki, Japan

Ogata, Tsuyoshi; Tanaka, Hideo; Irie, Fujiko; Nozawa, Yumiko; Noguchi, Etsuko; Seo, Kayoko; Tanaka, Emiko

doi:10.35772/ghm.2021.01116

Cited by 3 publications

(5 citation statements)

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“…For diseases where a correlation exists between symptoms and mortality, an intervention that only converts symptomatic individuals into asymptomatic individuals may reduce mortality. Ironically, the theory predicts that such an intervention will increase R 0 [270]. Conversely, the HI-STR model explains why the SARS-CoV2 Delta's higher symptomatic ratio [270] is associated with lower reproductive numbers.…”

Section: Discussionmentioning

confidence: 96%

“…Ironically, the theory predicts that such an intervention will increase R 0 [270]. Conversely, the HI-STR model explains why the SARS-CoV2 Delta's higher symptomatic ratio [270] is associated with lower reproductive numbers.…”

Section: Discussionmentioning

confidence: 96%

“…A cohort (n = 24) of post-vaccination breakthrough infection had a 100% symptomatic fraction [333]. Retrospective surveys indicate that 85-90% of the vaccinated are symptomatic vs 70-80% of the unvaccinated [252,253,270].…”

Section: Appendix B: Usa States' Basic Reproduction Number Outliersmentioning

confidence: 99%

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Reproduction number projection for the COVID-19 pandemic

Benjamin

2023

Adv Cont Discr Mod

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The recently derived Hybrid-Incidence Susceptible-Transmissible-Removed (HI-STR) prototype is a deterministic compartment model for epidemics and an alternative to the Susceptible-Infected-Removed (SIR) model. The HI-STR predicts that pathogen transmission depends on host population characteristics including population size, population density and social behaviour common within that population.The HI-STR prototype is applied to the ancestral Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) to show that the original estimates of the Coronavirus Disease 2019 (COVID-19) basic reproduction number $\mathcal{R}_{0}$ R 0 for the United Kingdom (UK) could have been projected onto the individual states of the United States of America (USA) prior to being detected in the USA.The Imperial College London (ICL) group’s estimate of $\mathcal{R}_{0}$ R 0 for the UK is projected onto each USA state. The difference between these projections and the ICL’s estimates for USA states is either not statistically significant on the paired Student t-test or not epidemiologically significant.The SARS-CoV2 Delta variant’s $\mathcal{R}_{0}$ R 0 is also projected from the UK to the USA to prove that projection can be applied to a Variant of Concern (VOC). Projection provides both a localised baseline for evaluating the implementation of an intervention policy and a mechanism for anticipating the impact of a VOC before local manifestation.

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Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 96%

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Reproduction number projection for the COVID-19 pandemic

Benjamin

2023

Adv Cont Discr Mod

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“…Once organised testing was up and running, a proportion of the true SARS-CoV-2 infected will still have been missing among those who were asymptomatic and did not seek testing [ 31 ]. Overtime, the proportion of asymptomatic SARS-CoV-2 carriers in the population may have fluctuated owing to the replacement of the original circulating SARS-CoV-2 variants with newer variants [ 32 ]. Furthermore, during the Omicron epidemic in Finland at the beginning of 2022, contact tracing and testing capabilities were overwhelmed, leading to a change in testing guidelines [ 5 ].…”

Section: Discussionmentioning

confidence: 99%

Seroepidemiological assessment of the spread of SARS-CoV-2 among 25 and 28 year-old adult women in Finland between March 2020-June 2022

Gray,

Eriksson,

Skoglund

et al. 2024

PLoS ONE

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Introduction Serological surveys of the prevalence of SARS-CoV-2 are instrumental to understanding the course of the COVID-19 epidemic. We evaluate the seroprevalence of SARS-CoV-2 among young adult Finnish females residing in 25 communities all over Finland from 2020 until 2022. Methods Between 1st March 2020 and 30th June 2022, 3589 blood samples were collected from 3583 women born in 1992–95 when aged 25 or 28 years old attending the follow-up of an ongoing population-based trial of cervical screening strategies. The crude and population standardized SARS-CoV-2 seroprevalence was measured using nucleocapsid (induced by infection) and spike wild-type (WT) protein (induced both by infection and by vaccination) antigens over time and stratified by place of residence (inside or outside the Helsinki metropolitan region). Results During 2020 (before vaccinations), spike-WT and nucleocapsid IgG antibodies followed each other closely, at very low levels (<5%). Spike-WT seropositivity increased rapidly concomitant with mass vaccinations in 2021 and reached 96.3% in the 2nd quartile of 2022. Antibodies to nucleocapsid IgG remained relatively infrequent throughput 2020–2021, increasing rapidly in the 1st and 2nd quartiles of 2022 (to 19.7% and 56.6% respectively). The nucleocapsid IgG seropositivity increased more profoundly in participants residing in the Helsinki metropolitan region (4.5%, 8.4% and 43.9% in 2020, 2021 and 2022 respectively) compared to those residing in communities outside the capital region (4.5%, 4.3% and 34.7%). Conclusions Low SARS-CoV-2 infection-related seroprevalence during 2020–2021 suggest a comparatively successful infection control. Antibodies to the SARS-CoV-2 WT spike protein became extremely common among young women by the end of 2021, in line with the high uptake of SARS-CoV-2 vaccination. Finally, the rapid increase of seroprevalences to the SARS-CoV-2 nucleocapsid protein during the first and second quartile of 2022, imply a high incidence of infections with SARS-CoV-2 variants able to escape vaccine-induced protection.

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“…Hence, we did not see any cross-infection in our study. These may be attributed to the low viral load, low infectivity of the first-wave strain, and low infectivity of asymptomatic patients [ 21 , 22 ]. As of now, most healthcare workers are vaccinated, and the safety of endoscopic procedures on RT-PCR-negative patients with the proper use of PPE kits will alleviate the fear of contracting infection among healthcare workers, with endoscopic facilities being available more easily to patients in this pandemic era.…”

Section: Discussionmentioning

confidence: 99%

Effect of the SARS-CoV-2 Pandemic on Gastrointestinal Endoscopy Procedures: Experience of a Tertiary Care Center From Eastern India

Kumar¹,

Jha²,

Roy³

et al. 2023

Cureus

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Background To contain the spread of infection and reduce the burden on healthcare infrastructure, many countries globally adopted a lockdown strategy during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Hospitals were converted to dedicated coronavirus disease 2019 (COVID-19) centers, and non-COVID-19 patients were intervened on a triage basis. During this time, only emergency procedures were performed. The impact of this lockdown strategy during the first wave of the SARS-CoV-2 pandemic on various gastrointestinal endoscopy interventions remains unknown. Methodology In this retrospective, observational study conducted in the Department of Gastroenterology, Indira Gandhi Institute of Medical Sciences, Patna, Bihar from March 25 to September 30, 2020, data related to clinical profile, indication, and endoscopic interventions performed in reverse transcriptase-polymerase chain reaction (RT-PCR)-negative patients with the use of personal protective kits were analyzed and compared with the historical controls. Results A total of 2,282 patients were admitted and 422 endoscopic procedures were performed during the six-month study period with an intervention rate of 18.49%. The most common procedure was upper gastrointestinal endoscopy (228, 58.13%), followed by endoscopic retrograde cholangiopancreatography (ERCP) (88, 22.50%). Chronic liver disease (CLD) (144 patients) followed by malignancy (111 patients) were the most common diagnosis. During the first phase of the lockdown (March to May), only 52 procedures were performed (52 vs. 506). None of the patients underwent endoscopic ultrasound. In 2019, 4,501 patients were admitted and 1,224 procedures were performed with an intervention rate of 27.19 (p < 0.0001). None of the staff of the Department of Gastroenterology developed symptomatic SARS-CoV-2 infection during this period. Conclusions There was a significant drop in endoscopic procedures during the lockdown and most of the esophagoduodenoscopy procedures were done for CLD and ERCP for biliary tract malignancy. Endoscopic procedures done on RT-PCR for COVID-19-negative patients were safe using personal protective kits.

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A low proportion of asymptomatic COVID-19 patients with the Delta variant infection by viral transmission through household contact at the time of confirmation in Ibaraki, Japan

Cited by 3 publications

References 10 publications

Reproduction number projection for the COVID-19 pandemic

Reproduction number projection for the COVID-19 pandemic

Seroepidemiological assessment of the spread of SARS-CoV-2 among 25 and 28 year-old adult women in Finland between March 2020-June 2022

Effect of the SARS-CoV-2 Pandemic on Gastrointestinal Endoscopy Procedures: Experience of a Tertiary Care Center From Eastern India

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